The personal dental service as a setting for an undergraduate clinical programme.

OBJECTIVE: To investigate the feasibility and benefits of placing dental undergraduates into a general dental practice setting for part of their clinical programme. SETTING: Two six-surgery general dental practices in the North West of England operating within the personal dental service of the NHS. METHOD: Six volunteer final year students worked within the practices for one-day-per week for 11 weeks. Evaluation included patients', practitioners' and students' views obtained from questionnaires and/or interviews and an analysis of students' clinical records. RESULTS: The students saw a large positive impact from: working alongside a dental nurse; developing their clinical skills; working in a busy practice environment; and developing interpersonal skills. Patients were very positive with 98% (44/45) being complimentary about the treatment they received, and commenting that they would be willing to participate in future student training programmes. The practice principals would also welcome continuation of the programme. CONCLUSION: The programme was both feasible and educationally beneficial. The financial implications need further research.

Case report: multiple myeloma--a rare presentation.

An unusual case of multiple myeloma is reported in a 61-year-old man presenting with hepatomegaly and multiple hypoechoic lesions in the liver seen on ultrasound. Following cytotoxic chemotherapy the size and number of the lesions within the liver had significantly reduced.

Study of the relative timing of shear forces on the sole of the forefoot during walking.

A portable recording device for the measurement of ambulatory longitudinal shear forces in a horizontal plane under the forefoot is described. The timing of the shear forces under 40 feet has been investigated, together with the relationships to each other and to body weight, leg length, cadence, velocity and stride length: they are compared by regression analysis. Shear forces under the forefoot are shown to occur for approximately 73-80% of the stance time. The maximum longitudinal shear forces and the maximum vertical forces are shown to occur at the same time under the first, fourth and fifth metatarsal heads.

Forces under the foot.

A transducer has been developed to record the shear or horizontal components of force beneath the sole of the foot. When used with a vertical force transducer it has enabled a comprehensive analysis of the mechanical forces acting beneath the foot when walking in various types of footwear. Considerable differences have been recorded between the footwear. Particularly low forces are present in a plaster cast and to a lesser extent with Plastazote insoles. The possible application of these findings to the management of ulceration of the sole of the foot in diabetes mellitus and leprosy is discussed.

The plain abdominal radiograph in pseudomembranous colitis due to Clostridium difficile.

The plain abdominal radiographs have been reviewed in nine patients with proven pseudomembranous colitis. These demonstrated small intestinal dilatation in eight patients, colonic thumb-printing and haustral thickening in seven, ascites in five and colonic dilation in two cases. The elucidation of these signs, especially in combination, may suggest the diagnosis of pseudomembranous colitis in those at risk.

Bronchial carcinoma presenting as autoimmune haemolytic anaemia.

A 68-year-old man presented with autoimmune haemolytic anaemia. Investigation revealed underlying bronchial carcinoma. A positive direct Coombs' test failed to revert to negative after removal of the primary tumour. This suggested the presence of metastases which was subsequently shown. The possible significance and origin of the autoantibody is discussed.

Characterization and localization of human placental ferritin.

Ferritin has been purified from normal full-term human placentae and its antigenic and molecular characteristics compared with adult liver ferritin. Placental ferritin is composed predominantly of a single subunit type, co-migrating with a liver ferritin standard on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Comparison of dose-response curves in an immunoradiometric assay indicated some tissue-specific antigenicity for placental ferritin. This was supported by immunofluorescence studies on cryostat sections of human placentae by using antibodies to placental and spleen ferritin. Specific staining for placental ferritin was demonstrated within placental syncytiotrophoblast, particularly localized towards the microvillus plasma membrane. Ferritin has also been shown by electrophoretic and antigenic analysis to be present in protein fractions solubilized from isolated human syncytiotrophoblast microvillus plasma-membrane preparations, suggesting that ferritin may play an active role in the transfer of iron from maternal transferrin across the syncytiotrophoblast plasma membrane.

An examination of the xenon clearance method.

A definition of cortical and juxta-medullary regions is suggested based on a grouping of nephrons of common flow characteristics. A possible error is suggested in the xenon clearance method of measuring the regional flows. Experiments to test the source of error and its magnitude are described. It is concluded that while the error is present its effect on conventional component analysis is small.

The renal blood flow and the glomerular filtration rate of anaesthetized dogs during acute changes in plasma sodium concentration.

1. The effects of acute changes in plasma Na concentration (P(Na)) on renal blood flow (RBF) and glomerular filtration rate (GFR) were studied in anaesthetized greyhounds. Saline was infused at a constant rate (0.1 ml. kg(-1) min(-1)) either into a renal artery or into a systemic vein. Plasma Na concentration was altered by varying the Na concentration of the infused saline from 0.154 to 0.077, 0.616 or 1.232 M.2. Blood pressure (B.P.), packed cell volume (PCV), concentration of plasma solids (PS) and the plasma concentration of H(+) and K (P(K)) ions were measured but no attempt was made to contain their fluctuation.3. An infusion of hypertonic saline into a renal artery usually led to an ipsilateral increase in RBF for 5-15 min, followed by a progressive fall. Over-all, mean values of RBF fell with P(Na) throughout the range studied (120-190 m-mole l.(-1)). Glomerular filtration rate rose with P(Na) to reach maximal values at P(Na) levels of 140-160 m-mole l.(-1), but fell thereafter. The combined fall in RBF and GFR, without change in filtration fraction, at P(Na) values above 160 m-mole l.(-1) is consistent with an alteration in afferent arteriolar resistance. The fall in GFR despite a rise in RBF noted when P(Na) was reduced below 140 m-mole l.(-1) requires an additional explanation.4. Renal blood flow was independent of P(K); it was inversely related to [H(+)] and directly related to PS. Glomerular filtration rate was independent of PCV and P(K). It was also inversely related to [H(+)] and directly related to PS up to a value of 6 g 100 g(-1) plasma, after which the relationship was reversed. These results suggest that the renal vascular responses to acute changes in P(Na) may be mediated in part, at least, by concurrent change in PS and [H(+)].

Plasma sodium concentration and sodium excretion in the anaesthetized dog.

1. The effect of acute alterations of plasma sodium concentration (PNa) on renal sodium excretion (UNaV) was investigated by three types of experiments on anaesthetized dogs: (a) A local increase in PNa at one kidney was produced by infusion of hypertonic saline directly into its artery while systemic levels of PNa were stabilized by haemodialysis. (b) Systemic levels of PNa were lowered by exchange transfusion of blood for an equal volume of salt-free dextran-in-dextrose solution. The results were contrasted with those observed after similar exchanges, but using dextran-in-saline solution. (c) The level of PNa was altered by varying the sodium concentration of a saline solution infused at a fixed rate either intravenously or into one renal artery. 2. All three types of experiment suggest a dependence of UNaV on PNa Analysis demonstrated that this relationship was not due to contemporary changes in: packed cell volume; plasma solids concentration; plasma potassium concentration; blood pressure or plasma hydrogen ion concentration. The distribution of these variables did not change with PNa except for plasma hydrogen ion concentration. Moreover, the relationship persisted when data were selected to exclude clearance periods in which the value for any variable had shifted past the group mean obtained before PNa was altered. 3. The fall in UNaV at low levels of PNa could be attributed to a fall in glomerular filtration rate (GFR), but the progressive rise in UNaV seen as PNa exceeded 150 m-mole 1(-1) occurred despite a fall in GFR and no apparent change in the mean filtered load of sodium. These results suggest that the increased sodium excretion accompanying raised levels of PNa is due to reduced tubular re-absorption of sodium.